Grass-Legume pastures to increase economic and environmental sustainability of livestock production

Grass-Legume pastures to increase economic and environmental sustainability of livestock production

Summary

The objective is to determine the potential of grass-legume pastures in comparison to grass monocultures. During this year, we reported that daily gain and dry matter intake was greater in steers grazing fertilized tall fescue as opposed to non-fertilized tall fescue. Grass-legume mixtures with energy supplements improved livestock nitrogen utilization efficiency. And grass-legume mixtures averaged 5 to 14% higher forage production than grass monocultures, with cicer milkvetch, birdsfoot trefoil and alfalfa mixtures most productive when they constituted 25, 25 and 50% of the mix, respectively. Overall, these results suggest that grass-legume mixtures can improve livestock and pasture productivity and sustainability.

Objectives/Performance Targets

Year 1: Begin grazing (plots established in 2009); measure feed intake, body weight, dry matter and nutrient digestibility (crude protein and fiber); and determine feed efficiency and plasma urea nitrogen during growing and finishing periods.

Year 2: Collect second year data on feed intake, body weight and dry matter and nutrient digestibility; determine feed efficiency and plasma urea nitrogen during growing and finishing period; and develop fact sheets for use at pasture walks and field days.

Year 3: Conduct continuous culture study using feed samples collected from growing and finishing periods to investigate ruminal fermentation characteristics (ammonia-N, VFA, methane, microbial protein synthesis and digestibility); evaluate meat quality of steers slaughtered after the finishing period in year 1 and 2 (FA analysis, tenderness, sensory panel evaluation, and lipid and color stability measurements); and revise fact sheets for symposium.

Year 4: Complete data analysis; and prepare journal manuscript(s).

Year 1: Plot establishment (seed plots and measure frequency of establishment).

Year 2: Begin grazing and collect first year of plot yield, nutritional quality and stand frequency; develop NIRS equation that separates species composition; and develop fact sheets for use at pasture walks and field days.

Year 3: Collect second year of plot yield, nutritional quality and stand frequency; and begin data analysis.

Year 4: Complete data analysis; revise fact sheet(s) and prepare journal manuscript.

Year 1: Pasture establishment; and collect baseline soil and leachate data.

Year 2: Begin grazing and collect first year of soil, plant and leachate data; sample analyses; and develop fact sheets for use at pasture walks and field days.

Year 3: Second year of collection of soil, plant and leachate data; sample analyses; and begin data analysis.

Year 4: Complete data analysis; revise fact sheet(s) and prepare journal manuscript.

Accomplishments/Milestones

Milestones for Year 1, 2, 3 and 4 have been completed for the component of comparing beef grazing grass with or without added fertilizer. Summary of results are listed here.

A two-year study was completed in 2012 evaluating beef steers grazing tall fescue (TF) pastures without or with nitrogen (N) fertilization and the resulting effects on growth performance, ruminal fermentation and carcass characteristics. In response to N fertilization, overall average daily gain (ADG) was greater (P<0.05) and dry matter intake trended upward (P=0.07) in steers that grazed TF+NF pastures (P<0.05). Regardless of N fertilization, ADG peaked between week 4 and 8 (1.05 kg/d; P<0.01) and then declined until week 16. Greater total volatile fatty acid (VFA) concentrations were detected in ruminal fluid of steers that grazed TF+NF (P<0.01), but only a minor effect was shown on individual VFA (acetate, propionate and butyrate) concentrations and acetate-to-propionate ratio. Back fat thickness, ribeye area and intramuscular fat concentration did not differ between treatments. Overall results of this study indicate that N fertilization on TF affected ruminal fermentation, which positively influenced growth performances, but did not affect carcass characteristics of grazing beef steers. In addition, readily fermentable carbohydrate supplementation is needed to improve utilization of increased dietary CP due to N fertilization and consequently enhance growth performances of grazing steers. This research was conducted in partial completion of a Ph.D. dissertation (Noviandi, C. T.). A peer reviewed journal article on this study was published in the Professional Animal Scientist. (Exhibit-Journal #1 and Journal #2).

Milestones for Year 1 and 3 have been completed for the component of comparing grass monoculture to low- and high-tannin-legume and grass mixtures. This study was delayed by a year due to legume die off and re-establishing grass-legume pastures. Summary of results to date are listed here.

An in vitro continuous culture study was conducted and completed in 2012 to investigate energy supplementation strategies on pasture forages to assess effects of energy supplementation [no concentrate, 30% ground corn, or 30% dried distilled grains with solubles (DDGS)] with four pasture forages [tall fescue (TF) without N fertilizer (TF-NF), TF with N fertilizer (TF+NF), TF-alfalfa mixture (TF+ALF), and TF-birdsfoot trefoil mixture (TF+BFT)] on vitro ruminal fermentation and N utilization. The results indicated that supplementing pasture forages with corn or DDGS enhanced microbial assimilation of ammonia-N and shifted metabolic pathways of microbial fermentation and methane gas production. Supplementation of corn in the TF+BFT elicited a similar ammonia-N concentration compared when corn was supplemented in the TF+NF. Therefore, grass-legume mixtures would be a sustainable component in grass grazing systems to improve N utilization efficiency with appropriate energy supplementation. This research was conducted in partial completion of a Ph.D. dissertation (Noviandi, C. T.). This study was recently presented at professional meetings. (Exhibit- Meeting #3).

The first year (2012) of a two-year study was completed evaluating beef steers grazing tall fescue (TF) pastures with or without low- and high-tannin legumes and the resulting effects on growth performance, ruminal fermentation and carcass characteristics. In response to grass-legume mixtures, the preliminary (1-year) average daily gains (ADG) were 0.82, 0.62, 0.62 and 0.27 kg/d for TF+BFT, TF+ALF, TF+NF, and TF-NF, respectively. Carcass quality and forage yield and quality data are being analyzed. The study will be repeated in 2013. This research is being conducted in partial completion of a M.S. thesis (Bingham, T.J.).

Milestones for Year 1, 2 and 3 have been completed for this objective. Summary of results are listed here.

Small plots of binary mixtures of five grasses [orchardgrass (OG), tall fescue (TF), meadow brome (MB), timothy, and perennial ryegrass (PR)] and three legumes [alfalfa (AF), birdsfoot trefoil (BF), and cicer milkvetch (CM)] were established, and yield data was collected for two years (2011, 2012). Ratios in the mixtures included 0, 25, 50 and 75% legume composition. Results revealed that tall fescue, OG and MB grass-legume mixes averaged 6.0, 5.0 and 14.0% higher forage production than their respective grass monocultures. The highest seasonal forage production of TF combinations was 1.62 Mg/ha TF:AF (50:50), 1.63 Mg/ha TF:BF (75:25) and 1.64 Mg/ha TF:CM (75:25). Highest forage production of OG combinations was 1.10 Mg/ha OG:AF (50:50), 1.09 Mg/ha OG:BF (75:25), and 0.99 Mg/ha OG:CM (75:25). Highest seasonal forage production of MB combinations was 1.23 Mg/ha MB:AF (50:50), 1.25 Mg/ha MB:BF (75:25) and 1.11 Mg/ha MB:CM (75:25). These results suggest that grass-legume mixtures can be an effective strategy to improve pasture productivity. Mixtures with cicer milkvetch and birdsfoot trefoil were most productive when they constituted 25% of the mix, whereas, mixtures with alfalfa were most productive when it comprised 50% of the mix. This research was presented at two professional meetings and was conducted in partial completion of a M.S. thesis (Cox, S.). (Exhibit-Meeting #4 and Meeting #5).

Milestones for Year 1 and 2 have been completed for this objective. This study was also delayed by a year due to legume die off and re-establishing grass-legume pastures. Summary of results are listed here.

The paddocks were established, and baseline soil samples were collected in the fall of 2011. Grazing and data collection began in 2012. Soil samples, three depths to a depth of 150 cm, were taken at the beginning and end of the grazing season. Leachate samples from zero-tension lysimeters were collected biweekly throughout the growing season and as often as possible during the winter months. Soil and leachate samples are currently being analyzed for available nitrogen (ammonia and nitrate) on a Lachate auto-analyer (QuickChem Method 10-107-04-1-C) and total N by combustion analysis. Leachate samples are being analyzed for nitrate-nitrite on a Lachat auto analyzer (QuickChem Method 10-107-04-1-C). Plant samples were taken before and after grazing events. A mass balance approach will be utilized to estimate nitrogen losses due to volatilization. No presentations or reports have been prepared for this component to date.

• Journal article on steer performance comparing fertilized and non-fertilizer grass
• Poster presentation of continuous culture study showing energy increased N utilization
• Abstract of Continuous culture study presentation
• Powerpoint presentation showing production of different ratios of mixtures of grass and legume
• Abstract of the presentation on grass legume ratios
• Journal article on fatty acid composition of pasture fed steers

Impacts and Contributions/Outcomes

Preliminary results indicate that steers perform better and have increased health and carcass quality when grazing grass that is fertilized or grown in mixture with legumes. In addition results of small-plot mixtures suggest that grass-legume mixtures are as productive as fertilized grass monocultures and that specific ratios between grasses and legumes further increase forage production. Two on-farm producer trials have demonstrated these findings to producers. A two-day grass-legume symposium is being planned in conjunction with the Utah State University pasture symposium for the summer of 2012. Overall, this information is adding to the knowledge-base about grazing grass-legume mixtures, and, with subsequent economic and environmental analyses, should lead to increased producer adoption and increased agricultural sustainability. Specific outreach and publications are listed below. Exhibit numbers have been given to them to allow citation in the results and naming for the annual report.

Ward, R. and B.L. Waldron. 2010. Franklin County Idaho Crop and Weed Tour. Tall fescue-legume mixtures to improve pasture sustainability. Western SARE grass-legume grazing plots on-farm field tour. Preston, ID. July 20, 2010. (Impact: 40-50 producers in attendance).

Waldron, B.L. 2010. Utah State University Pasture Research Workshop. Breeding and performances of pasture grasses and legumes. Utah State University Intermountain Irrigated Pasture Research Facility. Lewiston, UT. July 22, 2010. (Impact: 80-100 producers and extension personnel in attendance).

Heaton, K. Utah Cattleman’s Summer Tour. Western SARE grass-legume grazing plots on-farm field tour. Panguitch, UT. August 3, 2012. (Impact: 30-50 ranchers in attendance).

Heaton, K. Pasture walk for local conservation district and watershed committee. Western SARE grass-legume grazing plots on-farm field tour. Panguitch, UT. September 6, 2012. (Impact: 20-40 participants).

Noviandi, C. T., J.-S. Eun, D. R. ZoBell, R. D. Stott, B. L. Waldron, and M. D. Peel. 2011. Growth performance and carcass characteristics of beef steers grazing tall fescue without or with nitrogen fertilization. Pages 337–340 in Proceedings, Western Section, American Society of Animal Science, Montana State Univ., Miles City, MT, June 2011. (Exhibit-Meeting #1).

Noviandi, C. T., R. E. Ward, J.-S. Eun, D. R. ZoBell, R. D. Stott, T. Astuti, B. L. Waldron, and M. D. Peel. 2011. Fatty acid profiles in adipose tissue of grazing and feedlot beef steers. J. Anim. Sci. 89 (E-Suppl. 1):617. (Abstr.). Joint Annual Meeting of ADSA-ASAS, July 2011. (Exhibit-Meeting #2).

Noviandi, C. T., M. N. McDonald, D. R. ZoBell, J.-S. Eun, M. D. Peel, and B. L. Waldron. 2012. Effects of energy supplementation for pasture forages on in vitro ruminal fermentation in continuous cultures. J. Dairy Sci. 95 (Suppl. 2):45 (Abstr.). (Exhibit- Meeting #3).

Cox, S.R., M. Peel, B. Waldron, and E. Creech. Maximizing forage production with grass-legume mixtures of tall fescue, orchardgrass, meadow brome, alfalfa, birdsfoot trefoil, and cicer milkvetch in three ratios. Joint annual meeting of the Western Society of Crop Science and Western Wheat Workers; 2012 July 11-13; Pullman, WA. (Exhibit- Meeting #4).

Cox, S.R., M.D. Peel, B. Waldron, and E. Creech. Forage production of grass-legume mixes in three ratios with tall fescue orchardgrass, meadow brome, alfalfa, birdsfoot trefoil, and cicer milkvetch. ASA, CSSA, and SSSA, International Annual Meetings; 2012 October 21-24; Cincinnati, OH. (Exhibit-Meeting #5).

Noviandi, C. T., R. E. Ward, D. R. ZoBell, R. D. Stott, B. L. Waldron, M. D. Peel, and J.-S. Eun*. 2012. Fatty acid composition in adipose tissue of pasture- and feedlot-finished beef steers. Prof. Anim. Sci. 28:184–193. (Exhibit-Journal #1).

Noviandi, C. T., B. L. Waldron, J.-S. Eun*, D. R. ZoBell, and M. D. Peel. 2012. Growth performance, ruminal fermentation profiles, and carcass characteristics of beef steers grazing tall fescue without or with nitrogen fertilization. Prof. Anim. Sci. 28:519–527. (Exhibit-Journal #2).

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